What should I do with my visa when I renew my UK passport while in Thailand?

I think the O/P has all the info they need to get the stamps transferred when they get their new passport

Ok, the O/P is from the UK and they don't renew their passports thru their embassy here but thru the company VFS Global in the Trendy Building on Sukhumvit Soi 13.

@Steve ********

when you get your new passport they will also give you a letter addressed to the immigration office asking that your stamps be transferred. You take the old passport, the new passport and the letter along with the transfer stamp form filled out and these copies

After you get your old passport back, and your new passport, you should get a letter from the UK Embassy of Thailand asking the Thai government to transfer your current EXTENSION OF STAY from your old passport to your new passport.

IF you have a VISA STICKER (A full page sticker that says NON-O, and probably classified as a Non-OA), then it WILL NOT be transferred.